There are various passive electronic components known in the art for use in electronic circuits. Such passive electronic components include, but are not limited to, resistors, inductors and capacitors. Capacitors generally consist of one or more pairs of thin conductor plates separated by a non-conducive layer. The conductive plates extend uniformly over an area, and are usually made of metal. The non-conductive layer is formed of a dielectric material with a permittivity ∈. Such dielectric materials include, but are not limited to, ceramic materials, glass materials, paper materials, mica materials (e.g., silver mica) and plastic materials (e.g., polycarbonate, polyester, polystyrene and polypropylene).
The capacitor is characterized by a capacitance C defined by the following mathematical equations (1).C=Q/V=Q/[Qd/∈A]=∈A/d  (1)where C represents the capacitance of the capacitor. Q represents the ratio of charges on the facing surfaces of the conductive plates. V represents the voltages between the conductive plates. d is the distance between the conductive plates. A represents the “active area”, i.e, the area described by the overlap of two (2) conductive plates. As evident from mathematical equation (1), the capacitance C increases with area A and decreases with separation d. As also evident from mathematical equation (1), the capacitance C is greatest in capacitors having a non-conductive region made from dielectric materials with a high permittivity ∈.
Micro-Electro-Mechanical Systems (MEMS) technology is currently being used to form capacitors on semiconducting substrates. These capacitors are referred to herein as “MEMS capacitors”. The MEMS capacitors typically have at least one dimension between 1 to 100 micrometers (i.e. 0.001 um to 0.1 um). The MEMS capacitors typically comprise a plurality of stacked conductive plates disposed on the semiconducting substrate so as to extend horizontal to a surface of the semiconducting substrate. Each of the conductive plates typically has a height-to-width (h/w) ratio substantially less than one (1). As noted above, the capacitance C of the capacitor increases with the area A of the conductive layers. Therefore, larger valued MEMS capacitors take up more space on the semiconducting substrate as compared to the die space taken-up by smaller valued MEMS capacitors.
Although there have been improvements in the development of MEMS capacitors, there is a continuing demand for the reduction in the size of MEMS capacitors. Therefore, it is desirable to provide an improved MEMS capacitor design which requires less real estate on the die as compared to conventional MEMS capacitor designs.